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Discussion Starter · #1 ·
What are the advantages of upgrading the pulleys? They are kinda cheap. Would it be a good mod on stock?
 

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In essence, the lighter the pulley (the less rotating mass), the lighter the "load" on the engine. This, of course, leads to less power loss. Also, "underdrive" pulleys (smaller diameter than stock) will increase power due to their less weight and increased spinning (don't get this confused with putting a smaller pulley on a supercharger, though). Others will, I'm sure (hoping) chime in.
 

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yeah, because of the less weight & power it takes to spin the pulley, I guess you don't lose as much power to the wheels. You don't neccessarily gain power, but you gain control of some lost power to the wheels. If that makes sense. I guess it also causes your car to accelerate faster. But I'm no technical wizard, so don't quote me on that.
 

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i have an underdrive pulley, it was worth it, you can feel a teeny bit more "smoothness" when you accelerate. There is no discernable loss in alternator performance whatsoever, or ac or anything for that matter. It is sorta a biotch to get the crank pulley off you need to bust out the old breaker bar and soak the thing in wd40
 

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Underdrive pulleys help in two ways:

1) Less rotational inertia due to lighter weight lets the reciprocating assembly (crank, rods, pistons, flywheel) accelerate up to speed more quickly. (See also: lightened flywheel)

2) A smaller crankshaft (drive) pulley causes all the driven accessories to slow down. (Some pulley sets include a smaller alternator pulley to speed it back up.)

Smaller drive pulley = driven loads slow down
Smaller driven pulley = driven load speeds up (small SVT Lightning supercharger pulley on a new Cobra = more boost)

When your driven accessories slow down, the horsepower and torque that was needed to spin them at a higher RPM is no longer needed and transfers to the wheels.
 

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Discussion Starter · #6 ·
I'd like to do some mods to my engine, but I don't want anything major right now so I don't void the warranty.

Would this be pointless to do as one of my first engine mods?
 

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hello guys, since we are on the subject.....

no voltage loss after the pulley mod (which was one of my main concerns) but now another concern has arisen,

does anyone know if putting in a subwoof system is a good idea now that i've done this pulley install? or should i just grab a capacitor??

--RaCinWRX
 

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I'll play devil's advocate on this one.

In a non-balanced motor, solid pulleys remove any dampening effects that the stock pulley had. This *can* cause damage to crank bearings.

The EJ20 is a fairly balanced motor from the factory. I think it would be a worthy mod.

However, I have seen claims of odd resonances when used in conjunction with a lightweight flywheel. Maybe the stock pulley and flywheel cancel each other out from the factory? :confused:
 

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racinwrx, i have a subwoofer installed in my car....nothing huge cause im more about speed then sound...i think im running like 4 somthing hundred watts rms....when the car is idiling and the bass hits hard the voltmeter i installed blips to about 13 volts instead of 14 when the alt is recharging the battery. But when im driving around there is no loss noted on the vm.
 

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Here's something I kinda learned after getting my alternator replaced (so take it for what it's worth).

When you put an excessive load on the car's electrical output (ie big amp, big speakers), although the stock alternator can "handle" it, it may, in the long run, shorten the life of the alternator.

Alternators are not made to be constantly running. A regulator let's it know when to run or not to charge the battery. A constant large load on the battery will make the alternator run more frequently and duration. This may lead to the alternator failing. There are fixes for this, but I don't know them :(
 

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Alternators are not made to be constantly running. A regulator let's it know when to run or not to charge the battery. A constant large load on the battery will make the alternator run more frequently and duration. This may lead to the alternator failing. There are fixes for this, but I don't know them :( [/B][/QUOTE]

<<(If)>> you have a Aftermarket Sound system, that will drain the stock battery quick! Try upgrading to a dry cell series battery. $120.00 or so... and I would recommend a Lighting cap $150.00. That will keep a more constant voltage to all your accessories. Every time That Sub or Sub's hit... it will try to pull juice from every electrical source.

In my last car I had a decent system in it. every time my subs hit ( (4) 12" solobaric's, (2) zr1000 amps, zero gage wiring.) All my accessories would dim. And my car was stock. It was a FORD POS though. =)

Anyways before I installed my Gel battery and Lightning Cap my alternator went within 4 months. After installing those items I was set.


Just bolt on a TURBO if you want more power! :p



Vf-30
K&N Drop in
Blitz bov
TXS MBC
TXS Unichip
Godspeed Uppipe
Godspeed Downer
No Cats
Apexi World Sport Exhaust

Soon to come
Injectors
PE Fuel Pump
Blitz FMIC

This is getting expensive
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